Pressure sensitive record material



PRESSURE SENSITIVE RECORD MATERIAL Barrett 1K. Green, Dayton, Ohio, assigno'r to The National Cash Register Company, Dayton, Ohio, a corporation of Maryland No Drawing. Original application November 8,

1947, Serial No. 784,938. Divided and this application November 10, 1948, Serial No. 59,426

20 Claims.

t This invention relates to improvements in pressure-sensitive record material. This application is a division of the pending application of Barrett K. Green, Serial No. 784,938, filed November 8, 1947, for Pressure-sensitive record material.

In short, it is the object of this invention to provide a pressure-sensitive record material in which the mark of distinctive color will be produced only at the points of application of localized pressure, and at no other points, and under The principal object of this invention is to pro- 5 o oth Condi ons. vide apressure-sensitive record material on which Another object of this invention is to D 'OVi a k of di ti tiv color may b produced by a pressure-sensitive record material in which the the mere application of localized pressure and mark O distinctive 00101" is produced y the C e which is not Subject t t disadvantages ical reaction of color-forming reactants, in the herent in the pressure-sensitive record material ce o a y l q ionizing medium therefordisclosed in United States Letters Patent No. A further object f this nti n is to p vi 2,299,693, patented October 20, 1942, on t 3pa pressure-sensitive record material in which a plication filed by Barrett K. Green on February mark of distinctive color is produced by a reaction 23 .194 t patent discloses a pressure sensi between solid particles of color-forming reactants. tive record material including the combination of Further Objects, and objects relating to details an insulating medium, a rupturable solid material and economics of n o c c will defi y a such as gum dammar, having included therein pear from the detailed description to follow. The interspersed droplets of a plurality of liquid re- Objects o s vention have been attained by agents, which are chemically reactive to produce 1311? Several dlm nts thereof described m dea distinctive color in the record material at the tall the fOlIOWmg p c ca on. ThlS 1nvenpoints of application of localized pressure theretion 13 clearly defined and Pomted out 111 the to, such pressure rupturing the insulating medium appended Clalmsto permit chemical reaction between the two In general, the Present mventior} conmmmajtes reagent5 two reagents disclosed in 5 a pressure-sensitive reCOI'd material comprlsmg, this patent are gallic acid and ferric ammonium in combination, a plurality of adsorption colorsulphate, each dissolved in glycerine. These reforming reactants, Such reactants being 9 agents are ionized by the glycerine, which constilooted that t y r a n t absence f a om tutes an ionizing medium, and the chemical reionizing medium for the reactants: to a action pmceeds by interchange of ions when t distinctive color when brought into adsorption t Solutions are allowed t mix, upon t contact with each other, and a solid insulating ture of the insulating medium. The reaction dismedium insulating said reactants from colorclosed i th t patent depends upon th presence forming reaction contact with each other. Upon of the reagentsinan ionizing medium. Howev r, application of localized pressure to the record any available ionizing medium is hygroscopic, material, as by drawing a y u a o t with the result that the record material made in a ing medium is rup at points of paccordance with this patent is sensitive to an exp of said localized p s a Such pcess of moisture, and conditions of high humidity turc p s l min r act n contact b may cause the insulating medium to cease to be tween the reactants at Such P0111135, in the abefiective, with the result that the chemical re- 40 m of any liq id ionizing m i m r ai reti t k m t t any application f actants. The result is that a mark of distinctive localized pressure, and the record material is @0161 is produced y e more ppl on of stained and discolored, so that it ceases to be localized useful. The color-forming reaction employed is of the,

As stated above, the principal object of the so-called, adsorption type in which an inorganic present invention is to provide a pressure-sensimaterial causes a color change in an organic ti record t l t t i t subjected to the material when in adsorption contact with it. defects and disadvantages of that disclosed in Of the reactant materials employed the or- PatentNo. 2,299,693,- aS indicated above. ganic material is an electron donor aromatic Another object of the present invention is to compound having a double bond system which provide a record material upon which a mark of is convertible to a more highly polarized condistinctive @0101 y be P c at the Po jugated form upon taking part in an electron of application of localized pressure thereto, by acceptor-donor solid surface chemical reaction, such mere application of localized pressure, and giving it a distinctive color, and the inorganic which will not become discolored or stained due material is a material which is an acid relative to the efiect of light, amospheric conditions, or aging.

to the organic material so as to be an electron acceptor when in adsorption contact therewithi Both materials are in fine particle form in order to furnish a large reactant surface area per unit area of the record material which enhances the depth of color per unit area of the record material.

In the preferred form of this invention, both of the color-forming reactants, as well as the insulating medium, are in the solid state, and the color-forming reaction takes place upon mere contact of solid particles of the reactants. A pressure-sensitive record material may be provided in which the solid particles of a plurality of color-forming reactants are dispersed in a solid insulating medium, which insulates the particles from color-forming reaction contact with each other. The rupture of this solid insulating medium by the application of localized pressure permits the solid particles of colorforming reactants to react with each other, at the points of application of such pressure, to produce the mark of distinctive color. According to one form of this invention, solid particles of one of the color-forming reactants are carried by and dispersed in a solid insulating medium, to which a coating of solid particles of another color-forming reactant is applied. In this case, the application of localized pressure ruptures the solid insulating medium at the points of application of such pressure and brings about colorforming reaction contact between the solid par ticles of color-forming reactants at such points, thus producing the mark of distinctive color. Preferably, this pressure-sensitive record material includes a base web such as a fibrous web of paper or the like, to which the coating of solid insulating medium and the color-forming reactants is applied.

Since it is difficult to show precisely the spatial relationship between the solid particles of colorforming reactants, the solid insulating medium, and the base web, it is preferred not to attempt to illustrate any embodiment of this invention The casein constitutes the solid insulating medium, which insulates the solid particles of kaolin from color-forming reaction contact with the solid particles of 3,3 bis(p-diethylaminophenyl) phthalide. The material is normally white, but application of localized pressure thereto, as by drawing a stylus across it, produces a blue-green mark at the points of application of such pressure, due to the localized rupture of the insulating medium, permitting color-forming re 4 action contact between the reactant particles at such points.

This record material was made by first coating a web of paper with a casein solution having particles of kaolin dispersed therein, the ratio of kaolin to casein being about ten to one. This coated paper having been dried, its coated side was next treated with a 3% by weight solution in toluene of the compound 3,3 bis(p-diethylaminophenyl) phthalide. The excess of solution was then removed, and the treated paper was dried to evaporate the solvent.

Another pressure-sensitive record material constituting an embodiment of this invention consists of a web of paper having applied thereto a coating including casein as the solid insulating medium and solid particles of two color-forming reactants; namely, kaolin and the compound 3,3 bis(p-di n-propylaminophenyl) phthalide, having the structural formula This record material is normally white, and the solid insulating medium, casein, insulates the solid particles of kaolin from color-forming reaction contact with the solid particles of the compound 3,3 bis(p-di n-propylaminophenyl) phthalide, but the application of localized pres sure to this record material ruptures the insulating medium and permits color-forming reaction contact between the solid particles of the two reactants, thus producing a blue-green mark at the points of application of such pressure.

This record material has been made success-I fully by first coating a web of paper with a casein solution having solid particles of kaolin dispersed therein, the ratio of kaolin to casein being about ten to one. This coating having been dried on the paper, the coated side of the paper was then treated with a 3% by weight solution in toluene of 3,3 bis(p-di n-propylarninophenyl) phthalide. The excess solution was removed, and the treated paper was dried to evaporate the solvent.

When either of these coatings are applied to the paper, such coating should weigh about .0023 pound per square foot of surface and may have a thickness of the" order of from .0005 to .001 inch. The thickness of the coating varies, of course, with the treatment to which the record material is subjected in finishing. The solid particles of kaolin in this record material may be of about the order of ten microns in diameter, although considerable variation in particle size is possible without any ill effects. Particle size of the phthalide compounds is largely determined by the method of application of those ingredients. The particles of these reactants may be as large as ten, microns in diameter and frequently are much smaller.

Organic film-forming hydrophilic colloid substances such as gelatin, methyl cellulose, starch, polyvinyl alcohol, and animal glue are representative materials that may be substituted for casein as the solid insulating medium. Any of the following inorganic materials may be substituted for kaolin as one of the color-forming reactants attapulgite (Attapulgus clay), prophyllite, talc;

atonemcombination, the resulting record material will be white or bluish white in color, and abluegreen mark will appear thereon as the result of the application of localized pressure.

One method that has been used successfully to make the pressure-sensitive: record materials described above is as follows: A slurry of kaolin and water was prepared including fifty parts by Weight of kaolin to fifty parts by weight of water, and a small amount of a suitable dispersing agent, such. as sodium metaphosphate, for instance, in the proportion of 0.075% by weight was added to facilitate the dispersion of the particles of kaolin throughout the slurry. The addrtion of this dispersing agent reduces the viscosity of the slurry considerably; thus facilitating its mixing and application and also preventing the settling of the solid particles of kaolin. A 20% by weight solution of casein in water was formed by, first, dispersing the casein in cold Water by stirring for fifteen minutes at room temperatureand, then, heating up to 60 degrees centigrade. Five parts by weight of a 28% ammonium hydroxid solution-that is, one having a specific gravity of 25.9 B., at

were then added to the hot casein solution, which was stirred for about fifteen minutes and allowed to cool to room temperature. The kaolin slurry and the alkaline casein solution were then thoroughly mixed and blended in the ratio of ten parts by weight of kaolin to one part of casein, and, at this stage, a small percentage-401' in stance, about 0.05% by weight-of tributyl phosphate in alcohol, or other anti-foaming agent, was added. This mixture of the kaolin slurry and the casein solution was then applied as a coating to the paper, and the coated paper was dried and calendered or treated in any desired way to give the proper surface finish. A solution in toluene of about 3% by weight of the selected phthalide compound was then applied to the coated side of the paper, the excess of this a solution was removed in any suitable way, as by passing under a doctor blade, and then the treated paper was dried to evaporate the toluene and was ready for use.

The methods and processes of making pressure-sensitive record material disclosed herein are not claimed in this application but are disclosed and claimed in the pending application of Barrett K. Green, Serial No. 784,939, filed November 8, 1-947, for Process for making pressure-sensitive record material, and in the division thereof, Serial No. 63,215, filed December 2, 1948.

It is understood that the pressure-sensitive record material described herein is susceptible of considerable variation without departing from the spirit or" the invention.

What is claimed is:

1. Pressure-sensitive record material including the combination of as-upporting member, a plurality of adsorption color-forming reactants in the solid state, so selected as to react in the absence of a liquid ionizing medium for the reactants to form a distinctive color when brought into contact witheach othenat least one of said reactants being. an: inorganic compound. and at least another of. said reactants being anorganic compound, disposed in proximity to each other, and a solid insulating medium derived from an organic film-forming hydrophilic colloid substance, insulating said reactants from colorforming reaction contact with eachother, the application of localized pressure to the record material rupturing. said. insulating medium at the points of application of such pressure to. permit color-forming reaction contact between the reactants at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, one of said color-forming reactants being the organic compound or the general structure wherein R, is selected from the group consisting of the ethyl radical (G2H5) and the normal propyl radical (n-CaI-Iv), and the inorganic'reactant being in fine particle form providing a large adsorbent surface area and which is an acid rela tive to the organic compound so as to be an electron acceptor when inadsorption contact with the organic compound; said organic compound and inorganic material being adsorbable one upon the other.

2. The record material of claim 1 in which the inorganic color-forming reactant is kaolin.

3. The record material of claim 2 in which the solid insulating medium is casein.

4. Pressure-sensitive record material including the combination of a supporting member, solid particles of a plurality of adsorption colorforming reactants disposed in contiguity to each other, and a solid insulating medium, derived from organic film-forming hydrophilic colloid substance, insulating said solid reactant par' ticles from color-forming reaction contact with each other, at least one of the. reactants being an inorganic compound and at least another" one of the reactants being an organic compound adsorbable one on the. other, said reactants being. so selected as to react to form a distinctive color when particles of each are brought into adsorption contact, the application of localized pressure to the record material rupturing said insulating medium at the points of application of such pressure to permit color-forming reaction contact of the solid reactant particles at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, one of said color-forming reactants being an organic compound of the general structure wherein R is selected from the group consisting is of the ethyl radical (CzI-Is) and the normal propyl radical (l'l-CsHq), the inorganic reactant being in fine particle form to provide a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound.

5. The record material of claim 4 in which the inorganic color-forming reactant is kaolin.

6. The record material of claim 5 in which the solid insulating medium is casein.

7. Pressure-sensitive record material including the combination of a supporting member, a solid insulating medium derived from an organic film-forming hydrophilic colloid substance, solid particles of a first color-forming reactant dispersed therein and solid particles of a second color-forming reactant deposited thereon, said solid insulating medium insulating said solid re actant particles from color-forming reaction contact with each other, one of said reactants being an inorganic compound and the other of said reactants being an organic compound one adsorbable upon the other, said reactants being so selected as to react, in the solid state, to form a distinctive color when brought into adsorption contact with each other, the application of localized pressure to the record material rupturing said insulating medium at the points of application of such pressure to permit color-form-' ing reaction contact of the solid reactant particles at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, the second color-forming reactant being an organic compound of the general structure wherein R is selected from the group consisting of the ethyl radical (Cal-I5) and the normal propyl radical (n-CaI-Iv), the inorganic reactant being in fine particle form to provide a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound.

8. The record material of claim '7 in which the first color-forming reactant is kaolin.

9. The record material of claim 8 in which the solid insulating medium is casein.

10. Pressure-sensitive record material including the combination of a base web and a coating thereon, said coating including a plurality of adsorption color-forming reactants in the solid state, so selected as to react in the absence of an ionizing medium to form a distinctive color when brought into contact with each other, at least one of said reactants being an inorganic compound and at least another one of the reactants being an organic compound adsorbable therewith, and disposed in proximity to each other, and a solid insulating medium, derived from an organic film-forming hydrophilic colloid substance, insulating said reactants from color-forming reaction contact with each other, the application of localized pressure to the rec- 0rd material rupturing said insulating medium at the points of application of such pressure to permit color-forming reaction contact between the reactants at such points, whereby a mark of distinctive color is produced by mere application of localized pressure, one of the color-reactants being an organic compound of the general structure wherein R. is selected from the group consisting of the ethyl radical (C2H5) and the normal propyl radical (n-CaI-Iv), the inorganic reactant being in fine particle form to provide a large adsorbent surface area and which is an acid relative to the organic compound so as to be an electron acceptor when in adsorption contact with the organic compound.

11. The record material of claim 10 in which the inorganic color-forming reactant is kaolin.

12. The record material of claim 11 in which the solid insulating medium is casein.

13. The record material of claim 1 in which one of the color-forming reactants is the compound 3,3 bis (p-diethylaminophenyl) phthalide, having the structure 14. The record material of claim 4 in which one of the color-forming reactants is the compound 3, 3 bis (p-diethylaminophenyl) phthalide, having the structure 15. The record material of claim '7 in which one of the color-forming reactants is the compound 3,3 bis (p-diethylaminophenyl) phthalide, having the structure (C2Hs) zN- 03111:):

16. The record material of claim 10 in which one of the color-forming reactants is the com- 10 pound 3,3 bis (p-diethylaminophenyl) phthalide, 19. The record material of claim '7 in which having the structure one of the color-forming reactants is the compound 3,3' bis (p-di n-propylaminophenyl) (C2H5)2N M01115): phthalide, having the structure 5 0/ a 1): ON (CaH1):

0 t-o Q 17. The record material of claim 1 in which one of the color-forming reactants is the compound 3,3 bis (p-di n-propylaminophenyl) 20. The record material of claim 10 in which phthalide, having the structure one of the color-forming reactants is the compound 3,3' bis (p-di n-propylaminophenyl) (O:H1):N N(OIH7)D phtha-lide, having the structure 0/ aH-I):N aH1)= 18. The record material of claim 4 in which one of the color-forming reactants is the compound 3,3" bis (p-di n-propylaminophenyl) BARRETT K. GREEN. phthalide, having the structure REFERENCES CITED M0831) The following references are of record in the file of this patent: T FOREIGN PATENTS 0 Number Country Date 550,332 Great Britain Jan. 4, 1943 

1. PRESSURE-SENSITIVE RECORD MATERIAL INCLUDING THE COMBINATION OF A SUPPORTING MEMBER, A PLURALITY OF ADSORPTION COLOR-FORMING REACTANTS IN THE SOLID STATE, SO SELECTED AS TO REACT IN THE ABSENCE OF A LIQUID IONIZING MEDIUM FOR THE REACTANTS TO FORM A DISTINCTIVE COLOR WHEN BROUGHT INTO CONTACT WITH EACH OTHER, AT LEAST ONE OF SAID REACTANTS BEING AN INORGANIC COMPOUND AND AT LEAST ANOTHER OF SAID REACTANTS BEING AN ORGANIC COMPOUND, DISPOSED IN PROXIMITY TO EACH OTHER, AND A SOLID INSULATING MEDIUM DERIVED FROM AN ORGANIC FILM-FORMING HYDROPHILIC COLLOID SUBSTANCE, INSULATING SAID REACTANTS FROM COLORFORMING REACTION CONTACT WITH OTHER, THE APPLICATION OF LOCALIZED PRESSURE TO THE RECORD MATERIAL RUPTURING SAID INSULATING MEDIUM AT THE POINTS OF APPLICATION OF SUCH PRESSURE TO PERMIT COLOR-FORMING REACTION CONTACT BETWEEN THE REACTANTS AT SUCH POINTS, WHEREBY A MARK OF DISTINCTIVE COLOR IS PRODUCED BY MERE APPLICATION OF LOCALIZED PRESSURE, ONE OF SAID COLOR-FORMING REACTANTS BEING THE ORGANIC COMPOUND OF THE GENERAL STRUCTURE. 